Typically, hand cutters of the type that are used to sever work pieces, such as lengths of wire, operate either on the principle of compression cutting or of shearing. In either case, such cutters usually consist of pivotally joined members, each of which has a handle end and a cutter end, whereby closure of the handles produces corresponding closure of the cutting surfaces.
In compression type hand cutting tools, each cutting end is formed with surfaces that intersect each other at an acute angle to form a cutting edge. When the cutting ends are closed, the cutting edges abut each other substantially throughout their length. The effect is an incisor-like, pincer action which causes the work piece to separate under stress as the cutting edges are forced through it. This type of action usually operates well with workpieces which are small in size and/or made from material that is soft or malleable, such as copper. It usually is less effective with materials that are comparatively large unless they are very soft, or those which are comparatively hard, since severed segments of the piece may fly dangerously, and the cut end of the workpiece itself typically is left with a burr, a sharp point or a ridge. Further, the edges on such tools must be very hard and must be sharpened frequently since their effectiveness as cutting devices is largely dependent upon these factors and they function in an environment in which they are highly susceptible to wear. In addition, in order to get sufficient leverage to cut larger workpieces, the jaws must be opened widely, which compromises the leverage needed to effect a cut, particularly with harder materials.
In shearing action type devices, separation of segments from the work piece is effected by shear. In the manner of scissors, the cutting action is produced by causing the cutting edges of two flat blades to by-pass each other while the flat surfaces of the blades are in abutting contact. This type of action is particularly adapted for cutting comparatively soft, small workpieces, especially when in flat or sheet form, and is less likely to cause severed segments to fly or to produce points or to produce imperfections on the cut end of the workpiece. However, with such devices there is an increased tendency for workpieces to twist in response to the blade action, causing the blades to spring apart from each other as the workpiece becomes wedged between them. In view of this, using a shear type action mandates that the blades be made from heavy material to prevent these results from occurring, with consequent greater difficulty to form them into their desired shapes, and added cost, weight, and difficulties in sharpening and handling.
In both of these types of devices, the undesirable results of the suddenness with which severing can occur may not be limited to the cut segment flying, projectile-like, through the air, with the attendant dangers of that to personnel and equipment. In addition, the comparatively high work loads necessary to complete the severing operation, and the suddenness with which actual severance takes place, can have the effect of introducing a sever shock to the workpiece itself. If the situation is such that, for example, the wire or other workpiece being cut is attached to a sensitive or fragile or otherwise damage susceptible element, such as an electronic component, the resulting shock may be sufficiently severe to render the element inoperative, unreliable, or damaged.
While in either case it might be possible to retain segments cut off from a workpiece from flying dangerously through the air by means, such as shroud or a separate clamp, the disadvantages of having to resort to and separately manipulate such ancillary equipment are obvious. Further, to use such extra devices may restrict the orientation in which the cutting tool may be used, thus further complicating its use as a practical matter.
Accordingly, it is an object of this invention to provide means to cut segments from workpieces.
Another object of this invention is to provide such means that is adapted to cut comparatively hard materials.
Still another object of this invention is to provide means for satisfying one or more of the foregoing objectives that is adapted to cut comparatively large thickness or large diameter materials.
Another object of this invention is to provide means for satisfying one or more of the foregoing objectives that is adapted to retain segments cut from the workpiece after they have been cut from it.
Yet another object of this invention is to provide means for satisfying one or more of the foregoing objectives that is adapted to retain a large variety of diameters of cut workpieces.
A further object of this invention is to provide means for satisfying one or more of the foregoing objectives that is adapted to retain segments cut from the workpiece after they have been cut from it regardless of the positional orientation of the cutting means.
Still another object of this invention is to provide means for satisfying one or more of the foregoing objectives that is adapted to dampen mechanical shock resulting from the cutting operation from being transmitted along the workpiece.
Yet another object of this invention is to provide means for satisfying one or more of the foregoing objectives that is adapted to limit or prevent twisting of the workpiece being cut.